1. Field of the Invention
This invention relates to a lightweight soldering iron having a temperature control for soldering soft solders such as tin.
2. Description of the Related Art
Soldering irons may be divided into three categories. One category comprises a soldering iron with a simple switch control that applies full power to the soldering tip as soon as the switch is closed so that the soldering tip quickly reaches an operating temperature sufficient to melt the solder. A soldering iron in this first category draws a relatively constant amount of power with little regard to the amount of power actually required to melt solder. Thus, the temperature of the soldering tip is too low when the soldering iron is used to quickly melt a large amount of solder so that the soldering iron is ineffective. Increasing the power supplied to the soldering tip, however, can produce too high a temperature if the amount of power dissipated in melting the solder suddenly decreases. An excessive temperature may cause the soldering tip to become "burned" or to "alloy" with the solder and make the soldering tip inoperative.
A second category of soldering iron uses a continuously energized resistance element and controls the temperature of the soldering tip by dissipating excess heat. Soldering irons in this second category can easily overheat the soldering tip so that the solder alloys to the tip and makes the tip inoperative.
A third category of soldering iron uses a thermostatic control to interrupt the current supply whenever the soldering tip reaches an excessive temperature. This category of soldering iron requires a significant amount of time to adjust the current supply to compensate for a change in the temperature of the soldering tip.
The use of any known soldering iron to make, for example electronic circuit boards, requires the user to exercise great care to avoid burning the solder or to avoid damaging the circuit being soldered. These necessary precautions add considerable time to the soldering process and, hence, to the time required to produce a final product.